Kuibyshev Reservoir, Russian Federation

Home , Kama (river), Kuybyshev Reservoir, Samara (Volga), Sviyaga, Tolyatti, Volga

water

Article Shoreline Dynamics and Evaluation of Cultural Heritage Sites on the Shores of Large Reservoirs: Kuibyshev Reservoir, Russian Federation

Ionut Cristi Nicu 1,* , Bulat Usmanov 2 , Iskander Gainullin 3 and Madina Galimova 3 1 High North Department, Norwegian Institute for Cultural Heritage Research (NIKU), Fram Centre, N-9296 Tromsø, Norway 2 Department of Landscape Ecology, Institute of Environmental Sciences, Kazan Federal University, 5 Tovarisheskaya Street, 420097 Kazan, Russia; [email protected] 3 Khalikov Institute of Archaeology, 30 Butlerova Street, 420012 Kazan, Russia; [email protected] (I.G.); [email protected] (M.G.) * Correspondence: [email protected] or [email protected]; Tel.: +47-98063607

Received: 15 February 2019; Accepted: 20 March 2019; Published: 21 March 2019

Abstract: Over the last decades, the number of artiﬁcial reservoirs around the world has considerably increased. This leads to the formation of new shorelines, which are highly dynamic regarding erosion and deposition processes. The present work aims to assess the direct human action along the largest reservoir in Europe—Kuibyshev (Russian Federation) and to analyse threatened cultural heritage sites from the coastal area, with the help of historical maps, UAV (unmanned aerial vehicle), and topographic surveys. This approach is a necessity, due to the oscillating water level, local change of climate, and to the continuous increasing of natural hazards (in this case coastal erosion) all over the world. Many studies are approaching coastal areas of the seas and oceans, yet there are fewer studies regarding the inland coastal areas of large artiﬁcial reservoirs. Out of the total number of 1289 cultural heritage sites around the Kuibyshev reservoir, only 90 sites are not affected by the dam building; the rest had completely disappeared under the reservoir’s water. The scenario of increasing and decreasing water level within the reservoir has shown the fact that there must be water oscillations greater than ±1 m in order to affect the cultural heritage sites. The results show that the coastal area is highly dynamic and that the complete destruction of the last remaining Palaeolithic site (Beganchik) from the shoreline of Kuibyshev reservoir is imminent, and immediate mitigation measures must be undertaken.

Keywords: cultural heritage; shoreline dynamics; GIS; UAV; Palaeolithic; Volga; European Russia

1. Introduction The construction of large reservoirs along the large rivers of the world has, eventually, different effects: Local micro-climate modifications, disruption on the river flow regime [1], sediment transport [2,3], fauna [4], water chemistry [5], shore morphology [6–8], archaeology [9], fish yields [10], among other issues. They can also act as a place where different types of pollutants accumulate, and, in this way, it is easier to assess historical pollution [11]. One of the main effects is the triggering and the fast mechanic action of waves. These effects are accentuated by the global climatic changes, which are exponentially increasing every year. Many studies deal with risk assessment [12,13], management [14,15], vulnerability [16–18], conservation strategies [19,20] and sustainability issues [21] regarding the cultural heritage of the coastal areas of seas and oceans. However, there is a lack of studies dealing with inland shorelines of large man-made reservoirs [22]. The Volga River is the largest river in Europe with a basin area of

Water 2019, 11, 591; doi:10.3390/w11030591 www.mdpi.com/journal/water Water 2019, 11, 591 2 of 18 Water 2019, 11, x FOR PEER REVIEW 2 of 19

1,360,000 km2;; it it is is considered considered the the main main river river in Russia, and its basin represents the most significantsignificant economic region in Russia [[23].23]. During the the Soviet Union, there was a usual practice to flood flood large territories in order to obtain electricity electricity and and to to relo relocatecate a a large large number number of of inhabitants inhabitants and and their their houses. houses. Unfortunately, culturalcultural heritageheritage sitessites dodo notnot enterenter thisthis category;category; theythey cannotcannot bebe relocatedrelocated oror moved.moved. During the Soviet period (the late 1930s), the “Great Volga Scheme” was initiated; the purpose was the construction of a chain of dams along th thee Volga River and one of itsits majormajor tributaries—thetributaries—the Kama River. The reservoirs of the Volga-Kama casc cascadeade are one of the largest cascades in the world, totaling 11 reservoirs (Figure 11,, TableTable1 ).1). The The main main purpose purpose of of the the dams dams was was to to produce produce electricity; electricity; before the 1930s, the Volga was used only for transport and fishingfishing [[24,25].24,25]. As As shown shown in in Table Table 11,, Kuibyshev reservoir has the largest surface and thethe highesthighest numbernumber ofof typestypes ofof uses.uses. There have been limited studies referring to the destruction of archaeological sites around the Kuibyshev reservoir [26,27], [26,27], but but there there are are no studies referring referring to to the the entire entire surface surface of of the the reservoir. reservoir. Therefore, thisthis study study is is necessary necessary to assessto assess the exactthe exact number number of sites of impactedsites impacted by the reservoirby the reservoir creation creationin 1957 and in 1957 to draw and attention to draw forattention local authorities for local authorities in their mission in their for mission future management for future management plans [28] of plansthe shoreline [28] of the area shoreline [29]. A detailedarea [29]. case A detailed study was case chosen study towas demonstrate chosen to demonstrate the destructive the potentialdestructive of wavepotential erosion; of wave this erosion; was accomplished this was accomplished by a systematic by monitoringa systematic process. monitoring The mainprocess. scope The of main this articlescope ofis (1)this to article track theis major(1) to changestrack the of major the Volga changes River of after the theVolga construction River after of thethe Kuibyshevconstruction reservoir of the withKuibyshev the help reservoir of GIS (2) with to identify the help the of area(s) GIS that(2) containto identify the highestthe area(s) concentration that contain of archaeological the highest concentrationsites (3) to analyse of archaeological how many archaeological sites (3) to analyse sites were how impacted many archaeological following the sites construction were impacted of the followingreservoir (4)the to construction monitor the of evolution the reservoir of the (4) only to leftmonitor Palaeolithic the evolution site—Beganchik of the only from left the Palaeolithic shores of site—BeganchikKuibyshev reservoir, from which the shores has been of Kuibyshev specifically reserv chosenoir, becausewhich has of itsbeen high specifically erosion rates. chosen because of its high erosion rates.

Figure 1. DetailDetail of of the the reservoirs of the Volga-Kama cascade.

Water 2019, 11, 591 3 of 18

Table 1. The main characteristics of reservoirs from the Volga-Kama cascade [24,25] (the numbers in the ﬁrst column correspond to the reservoirs from Figure1).

Volume (km3) No. Crt. YOC RA (km2) IC (103 kW) AO (109 kWh) TOU Total Useful 1 1937 327 1.2 1 30 0.12 WNWrFPR 2 1940 249 1.2 0.8 110 0.25 PNWRF 3 1941 4550 25.4 16.6 330 1.05 PNWFFlWrRT 4 1956 1770 8.7 2.8 520 1.4 PNWFWrRT 5 1981 3780 12.6 5.4 1404 3.3 PNWRFWrT 6 1958 6500 57.3 33.9 2300 10.2 PNFIWFlWrRT 7 1968 1950 12.8 1.7 1290 5.3 PNWFlRTWr 8 1960 3165 31.4 8.2 2530 10 PNWFlFiWrRT 9 1956 1845 12.2 9.8 504 1.7 PTNFiWFRWr 10 1961 1130 9.4 3.7 1000 2.2 PNTWFiRWr 11 1978 2305 13.8 4.6 1080 2.8 PNTWFiRWr Legend: YOC—year of commissioning; RA—reservoir area; IC—installed capacity; AO—annual output; TOU—type of use; Fi—ﬁshery, Fl—ﬂood control, I—irrigation, Navigation, P—power production, R—recreation, T—timber rafting, W—water supply, Wr—water releases (sanitary, irrigation).

2. Study Area Kuibyshev reservoir is a result of the construction of the Zhiguli Hydroelectric Station, Samara region, located between Zhigulevsk city (right bank of the Volga) and Tolyatti (left bank of the Volga); the reservoir covers the territory of regions Chuvash, Tatarstan, Ulyanovsk, and Samara. Kuibyshev reservoir has a surface of 6450 km2, a volume of water of 58 km3, a length of approximately 510 km, a mean depth of 9.3 m; these impressive numbers make it the largest reservoir in Europe [30], with a sedimentation rate of 8 mm/year. Important changes occurred in what concerns the sedimentation rate, which has fallen to 2.7–2.9 mm/year, after the commissioning of the dam in 1957. One of the main sources of sediments is a result of the abrasion processes, collapses of a huge amount of sediments into the reservoir [25,31]. Our area of interest is located in Tatarstan region (Figure2a), on the left bank of Kuibyshev reservoir (Figure2b), at the junction of Kama River in the Volga, about 75 km south-east of the city of Kazan (the capital city of Tatarstan). Beganchik site is located at approximately 2.8 km North-east of Izmeri village and 1.5 km north-west of Komintern village, on an isolated hill of the terrace above the floodplain; on the left bank of the confluence of Kama and Volga rivers, at the mouth of Aktai river (Figure2c, Figure3a). The geology of the area consists of Permian, Pliocene and Quaternary deposits. Quaternary sediments are dominant in Volga-Kama terraces, eight palaeohydrological phases were identified from high and low fluvial activity; the most recent active phase corresponds to the Little Ice Age [32]. There is a limited number of studies regarding the evolution of the coastal area in the Tatarstan region, Russia [25], along with the analysis of landslides [33] and gully erosion [34]. Water 2019, 11, x FOR PEER REVIEW 4 of 19

Our area of interest is located in Tatarstan region (Figure 2a), on the left bank of Kuibyshev reservoir (Figure 2b), at the junction of Kama River in the Volga, about 75 km south-east of the city of Kazan (the capital city of Tatarstan). Beganchik site is located at approximately 2.8 km North-east of Izmeri village and 1.5 km north-west of Komintern village, on an isolated hill of the terrace above the floodplain; on the left bank of the confluence of Kama and Volga rivers, at the mouth of Aktai river (Figure 2c, Figure 3a). The geology of the area consists of Permian, Pliocene and Quaternary deposits. Quaternary sediments are dominant in Volga-Kama terraces, eight palaeohydrological phases were identified from high and low fluvial activity; the most recent active phase corresponds to the Little Ice Age [32]. Water 2019There, 11, 591is a limited number of studies regarding the evolution of the coastal area in the Tatarstan 4 of 18 region, Russia [25], along with the analysis of landslides [33] and gully erosion [34].

FigureFigure 2. Geographical 2. Geographical location location of: of: ( a()a) KuibyshevKuibyshev reservoir reservoir in ina regional a regional context; context; (b) Kuibyshev (b) Kuibyshev reservoirreservoir and the and cultural the cultural heritage heritage sites sites around around it;it; ( cc)) Beganchik Beganchik site site on onthe thetopographic topographic maps scale maps scale 1:50.000 (edition 1984). 1:50.000 (editionWater 2019 1984)., 11, x FOR PEER REVIEW 5 of 19

Figure 3. (a) AerialFigure image3. (a) Aerial of image Beganchik of Beganchik site site from from 2018; (b) ( bOverlapping) Overlapping Volga River Volga beforeRiver and after before and after the building of Kuibyshev reservoir, along with the inventory of archaeological sites. the building of Kuibyshev reservoir, along with the inventory of archaeological sites. 3. Archaeological Background

Water 2019, 11, 591 5 of 18

3. Archaeological Background

3.1. General Overview Ever since the Palaeolithic, large rivers and their fertile plains have been a magnet for prehistoric people to place their settlements; water is undoubtedly the most important resource that a community of people needs in order to decide where to place a settlement [35]. According to the local geographical factors and paleogeographic evolution of the landscape, the old location could be used by the next population of a different historic period. This is how multi-stratified archaeological sites were created. Around Kuibyshev reservoir, 1289 cultural heritage sites have been identified. The protection of cultural heritage assets in Russia was and is still a current issue, because of the country’s complex political background; at present, cultural heritage is protected by the Federal Law 73-F3, On the Objects of Cultural Heritage (Historical and Cultural Sites) of the Peoples of the Russian Federation [36]. In this area, the oldest traces are attributed to Upper Palaeolithic-Mesolithic period. The area surrounding the Volga River has tremendous potential in regard to cultural heritage sites of Palaeolithic [37,38], Mesolithic age [39], Neolithic [40], Chalcolithic/Bronze Age [41], Early Iron Age [42], Middle Ages, etc. The only remaining Palaeolithic site which has not been impacted by the reservoir is Beganchik. Besides the Palaeolithic site, Beganchik, around the Kuibyshev reservoir there are many archaeological sites of international and national significance; among them, the Bolgar archaeological site. The Bolgar Historical and Archaeological Complex are part of the UNESCO World Heritage List since 2014; it represents the existence of the Volga-Bolgar civilisation (7–15th centuries AD), and the first capital of the Golden Horde in the 13th century [25].

3.2. Beganchik Site Beganchik site was studied for the first time in September 1985 by M. Sh. Galimova and K. E. Istomin at the recommendation of E.P. Kazakov; the first description of the site is the islet named “the Izmeri Island”. In 1981, mammoth fauna fossils were found; they were located on the towing-path in the south-western part of the islet, at the foot of the narrow, long butte, which had the shape of a peninsula with a length of about 200 m. The discovered mammoth fossils were five teeth and leg bones, together with large flint nuclei and tools in an area of 20 × 20 m2. Unfortunately, by the year 2000, this peninsula was completely eroded by the Kuibyshev reservoir. In the next years, almost every autumn (until 2012) Kazakov collected stone artefacts and faunal remains at the south-western tip of the islet in conditions of low reservoir level [43]. M. Sh. Galimova in 1985–1987 and 2000 also conducted investigations of this site. In 1986, a reference point was installed at the highest point of the islet, therefore all excavations and trenches were referenced after it. An excavation area of 104 m2 was located on the edge of the steep west coast of the islet; the cultural layer has been found at 100–130 cm depth; 1968 of artefacts were found. The specific features of the Beganchik stone industry, which was based on blade production by means of striking technique and its flint inventory, allowed M. Sh. Galimova to frame the site of initial (Upper Palaeolithic) period of the Mesolithic Ust-Kama culture. The main diagnostic tool of the Ust-Kama inventory is the arrowhead in a trapezoid shape with concave sides, which were shaped by retouching [44]. In 2000, the rescue excavations of the site were continued by M. Sh. Galimova with the participation of I. I. Gainullin. By that moment excavation territory of 1986–1987 was eroded by the reservoir. In general, the western and northern coasts of the islet were washed away by 20–25 m from the erosion ledge for 14 years (1986–2000). In the autumn of 2012, rescue investigation of the Beganchik site and Izmeri I site was conducted by the expedition of the National Centre for Archaeological Research of the Tatarstan Academy of Sciences. In the autumn of 2013, rescue investigation on the Beganchik islet was continued by a joint campaign of the “Expedition for Prehistory” of the Institute of Archaeology of the Tatarstan Academy of Sciences and “Archaeological Expedition” of the Chuvash State Institute for Humanities. The total excavated area was 20 m2; following the excavation and Water 2019, 11, 591 6 of 18 surface findings, a significant collection of stone artefacts (439 items) and 80 bones of a mammoth were found [45].

4. Materials and Methods In order to determine the shoreline dynamics, topographic map scale 1:300,000 (edition 1945), and Google Earth images from 2010, were employed. From the topographic map, the extent of the Volga River before the reservoir construction was digitised; from Google Earth images from 2010, the extent of the reservoir was digitised. They were overlapped in ArcGIS and the highest differences were observed. The archaeological inventory, as a point feature, (Figure3b) was provided by the Institute of Archaeology of Tatarstan Academy of Sciences. The database was compiled over a long period of time, both prior and after the filling of the reservoir; first sites were described in the early 1940s until the early 1960s, when special survey expeditions were undertaken, with the aim to find as many sites and record brief information about them. After the filling of the reservoir, more expeditions were undertaken to highlight the impact on the sites. Other sources in building the database included the descriptions of the Archaeological Maps of Tatarstan, Ulyanovsk and Samara regions. A survey has been unsystematic across the study area, sites are located to varying degrees of accuracy and the full extent of individual sites is not necessarily known. The database is still under construction, as the area is very large and only a few people within the Institute of Archaeology of Tatarstan Academy of Sciences is working to continuously update it. However, it is the most comprehensive archaeological dataset which currently exists in this area, hence will be used for this study. Density analysis of the settlements for the main historical periods was performed; this was made using the Point Density feature (using the circle as neighbourhood option) from ArcToolbox (ArcGIS). The danger towards increasing and decreasing water level over the digital elevation model (DEM) was evaluated by making four working scenarios; the DEM used in this study is based on the Shuttle Radar Topography Mission (SRTM), with a pixel size of 30 × 30 m2. First, the water level was decreased by 0.5 m and 1 m, followed by increasing the water level with 0.5 m and 1 m, respectively. Changes in reservoir level regime occur out of two main reasons: Natural seasonal changes in the flow and artificial regulations of water discharge through hydraulic structures, the difference in baric pressure, wind speed and changes in the hydraulic slope. The water level of the reservoir is controlled by a special department—RusHydro. We chose these values taking into consideration our large-scale study area and to point out the minor oscillations in water level by arbitrarily increasing/decreasing it by ±0.5 to 1 m. In order to have a better image of the changes occurred along the Volga River after the Kuibyshev reservoir was built, the entire area was divided into three sectors, as follows: Sector 1 (Figure4b), Sector 2 (Figure4c), and Sector 3 (Figure4d). For monitoring the Beganchik site, a rich cartographic background, including Soviet aerial images from 1958 and 1980, Roscosmos aerial images (2008), and UAV flights [46] from the summer of 2017 and 2018 were used. As shown in numerous studies, old maps and aerial images are an important source of information [47] that can be easily digitised, integrated into GIS [48], and used in the field of cultural heritage [49,50]. All the maps and aerial photos have been georeferenced with the help of ArcGIS. The ground control points used for the drone flights were measured with a GNSS (Global Navigation Satellite System) receiver Trimble Geoexplorer 6000 XH and Leica Zeno 20. The UAV is a drone, model DJI Phantom 4. The survey was performed with a 12-megapixel camera mounted on the quadcopter; the UAV was controlled from a smartphone using Pix4D Capture software, which allows configuring the shooting parameters. Aerial photography was performed with the following parameters, height—70 m, picture overlapping—60–80%, camera position—90 degrees, meteorological conditions—no precipitation, and wind no more than 15 m/s. The photos were processed using the algorithms built into the Agisoft Photoscan software; the resulting model was processed by a polynomial approximation exponential kernel (PAEK) method with 1 m tolerance. Water 2019, 11, 591 7 of 18 Water 2019, 11, x FOR PEER REVIEW 8 of 19

Figure 4. (a) General division of the Kuibyshev reservoir; (b) Sector 1; (c) Sector 2; (d) Sector 3. Figure 4. (a) General division of the Kuibyshev reservoir; (b) Sector 1; (c) Sector 2; (d) Sector 3. 5. Results 5. Results Each sector will be analysed according to the GIS integration of the spatial data collected from old mapsEach andsector modern will be aerial analysed images, according followed to bythe the GIS analysis integration of the of archaeological the spatial data sites collected patterns from and olddynamics maps and along modern the Volga aerial River; images, then, followed the changes by the of analysis Volga River of the will archaeological be analysed sites in the patterns context and of dynamicshow many along cultural the heritageVolga River; sites arethen, directly the changes affected of by Volga the reservoir River will construction. be analysed The in the four context working of howscenarios many will cultural be analysed heritage in sites order are to directly evaluate affected the endangered by the reserv sitesoir towardsconstruction. increasing/decreasing The four working waterscenarios level will of thebe analysed reservoir. in Finally, order theto evaluate monitoring the results endangered of the onlysites lefttoward Palaeolithics increasing/decreasing site—Beganchik willwater be level presented; of the this reservoir. site has beenFinally, specifically the monito chosenring because results ofof its the high only erosion left ratesPalaeolithic and being site— the Beganchikonly remaining will be Palaeolithic presented; site this around site has Kuibyshev been specifically reservoir. chosen because of its high erosion rates and being the only remaining Palaeolithic site around Kuibyshev reservoir. 5.1. Volga River Dynamics 5.1. Volga River Dynamics From the town of Tver to Volgograd, Volga River flow velocity is affected by the 8 reservoirs. The reservoirsFrom the weretown builtof Tver to control to Volgograd, seasonal Volga changes River in flow; flow however, velocity thereis affected are no by significant the 8 reservoirs. changes whenThe reservoirs it comes towere river built discharge to control and the seasonal total annual changes discharge. in flow; In however, the middle there Volga, are the no mean significant annual changesflow from when 1876 it to comes 1940 was to river 2876 discharge m3/s; after and the the construction total annual of reservoirs,discharge. fromIn the 1942–1955, middle Volga, the mean the meanannual annual flow was flow 2780 from m 31876/s [51 to]. 1940 was 2876 m3/s; after the construction of reservoirs, from 1942– 1955,Sector the mean 1 (Figure annual5a) flow stretches was 2780 approximately m3/s [51]. in the north-western part, next to the Zvenigovo city tillSector south-east, 1 (Figure at the5a) junctionstretches betweenapproximately Volga andin the Kama north-western rivers; it has part, a length next to of the approximately Zvenigovo 145city km.till south-east, The most at important the junction cities between within Volga Sector and 1 are Kama Kazan rivers; (with it ahas population a length of of approximately about 1,2 mil. 145people) km. andThe Zelenodolskmost important (with cities a population within Sector of about 1 are 98,000 Kazan people). (with a Out population of the three of sectors,about 1,2 Sector mil. 1people) has the and fewest Zelenodolsk changes, (with compared a population with the of others; about the98,000 most people). significant Out of changes the three are sectors, located Sector about 143 has km the downstream fewest changes, from Kazancompared city. with Initially, the others Volga; hadthe most a width significant of 1.4 km, changes while afterare located the building about 43of thekm Kuibyshevdownstream reservoir from Kazan the width city. Initially, of Volga Volg reacheda had 9.5 a km.width Another of 1.4 km, significant while after change the isbuilding located ofbetween the Kuibyshev Zelenodolsk reservoir and Kazan, the width at the of junction Volga reached of Sviyaga 9.5 km. River Another in the Volga; significant from achange width is of located 0.6 km, Volgabetween reached Zelenodolsk a width and of 11.2 Kazan, km; at except the junction this, the of reservoir Sviyaga water River has in the mainly Volga; covered from thea width left side of 0.6 of km, Volga reached a width of 11.2 km; except this, the reservoir water has mainly covered the left

Water 2019, 11, x FOR PEER REVIEW 9 of 19 Water 2019, 11, 591 8 of 18 side of the river. This is due to the geomorphological characteristics of the area; the right side represents the Volga uplands, while on the left side are the terraced plains of the lowland Volga River theregion river. [52]. This is due to the geomorphological characteristics of the area; the right side represents the VolgaSector uplands, 2 (Figure while on5b) the stretches left side from are the east terraced to west plains on a ofdistance the lowland of approximately Volga River region150 km [ 52and]. representsSector the 2 (Figure lower5 b)Kama stretches River from junction east to to west Volga on aRiver; distance before of approximately the Kuibyshev 150 reservoir, km andrepresents the area thelocated lower around Kama Riverthe junction junction had to Volgaa significant River; beforenumber the of Kuibyshev villages (which reservoir, were the completely area located destroyed). around the junctionMoreover, had important a significant landscape number changes of villages occurred, (which along were with completely an acceleration destroyed). of coastal Moreover, erosion important with landscapea direct effect changes on occurred,cultural heritagealong with [25]. an The acceleration most important of coastal city erosion in this with sector a direct is Chistopol effect on (with cultural a heritagepopulation [25 ].of The approximately most important 60,0 city00 inpeople). this sector Along is Chistopolits approximately (with a population 150 km length, of approximately after the 60,000building people). of Kuibyshev Along itsreservoir, approximately Sector 2 150had kmmore length, or less after a balanced the building development of Kuibyshev of the right reservoir, and Sectorleft bank; 2 had this more is because or less both a balanced of the sides development are located of thewithin right the and terraced left bank; plains this of is the because lowland both Volga of the sidesRiver are region. located From within an average the terraced width plains of 0.8–1 of the km lowland, the Kama Volga River River reached region. widths From an of average 13–36.8 widthkm. ofFrom 0.8–1 these km, thenumbers, Kama Riverwe can reached realise widthsthe real of pr 13–36.8oportions km. of From the theseconsequences numbers, of we the can Kuibyshev realise the realreservoir proportions being built. of the consequences of the Kuibyshev reservoir being built.

Figure 5. Results of the coastal dynamics analysis for: (a) Sector 1; (b) Sector 2; (c) Sector 3. Figure 5. Results of the coastal dynamics analysis for: (a) Sector 1; (b) Sector 2; (c) Sector 3. Sector 3 (Figure5c), with a length of approximately 263 km, stretches from Kama and Sector 3 (Figure 5c), with a length of approximately 263 km, stretches from Kama and Volga Volga junction until the dam of the Zhiguli Hydroelectric Station, located between the cities of junction until the dam of the Zhiguli Hydroelectric Station, located between the cities of Zhigulyovsk Zhigulyovsk and Tolyatti. The most important cities in this sector are Tolyatti (with a population and Tolyatti. The most important cities in this sector are Tolyatti (with a population of approximately of approximately 720,000 people), Ulyanovsk (with a population of approximately 614,000 people) 720,000 people), Ulyanovsk (with a population of approximately 614,000 people) and Bolgar (with a and Bolgar (with a population of approximately 9000 people). Bolgar is well known for the Bolgar population of approximately 9000 people). Bolgar is well known for the Bolgar Historical and Historical and Archaeological Complex World Heritage site. Similar in development with Sector 1, Archaeological Complex World Heritage site. Similar in development with Sector 1, the left side of the left side of the river being more developed than the right one; again, this is to the lower altitudes of the river being more developed than the right one; again, this is to the lower altitudes of the terraced the terraced plains of the lowland Volga River region [52]. Within this sector, the width of the Volga plains of the lowland Volga River region [52]. Within this sector, the width of the Volga River before River before Kuibyshev reservoir was ranging from 0.7–2.1 km, and from 9.1–32.2 km after the building Kuibyshev reservoir was ranging from 0.7–2.1 km, and from 9.1–32.2 km after the building of of Kuibyshev reservoir. Having this enormous width, it is sometimes called the Kuibyshev Sea. Kuibyshev reservoir. Having this enormous width, it is sometimes called the Kuibyshev Sea. 5.2. Archaeological Site Analysis 5.2. Archaeological Site Analysis Following the analysis of the archaeological database provided by the Institute of Archaeology Following the analysis of the archaeological database provided by the Institute of Archaeology of Tatarstan Academy of Sciences, the following periods were identified: Palaeolithic/Mesolithic, of Tatarstan Academy of Sciences, the following periods were identified: Palaeolithic/Mesolithic, Neolithic, Chalcolithic/Bronze Age, Early Iron Age, Migration Period, and Middle Ages. Large river Neolithic, Chalcolithic/Bronze Age, Early Iron Age, Migration Period, and Middle Ages. Large river systems, e.g., the Volga, act as a magnet when it comes to taking a decision to place a prehistoric systems, e.g., the Volga, act as a magnet when it comes to taking a decision to place a prehistoric settlement. That is why, in the close proximity of the Volga River and its tributaries, there is a high settlement. That is why, in the close proximity of the Volga River and its tributaries, there is a high density of archaeological sites. Water represents the main resource in establishing the placement of density of archaeological sites. Water represents the main resource in establishing the placement of a a settlement; this is documented and well-known across the archaeologists and geo-archaeologists [53]. settlement; this is documented and well-known across the archaeologists and geo-archaeologists [53]. On the basis of the existing database, the areas with the highest concentration of archaeological On the basis of the existing database, the areas with the highest concentration of archaeological settlements attributed to a certain period will be identified and highlighted accordingly. Usually, settlements attributed to a certain period will be identified and highlighted accordingly. Usually, the the dynamics of the settlements are influenced by different factors, like climate change [54], natural

Water 2019, 11, x FOR PEER REVIEW 10 of 19 Water 2019, 11, 591 9 of 18 dynamics of the settlements are influenced by different factors, like climate change [54], natural hazards [55] and threats from other populations. Having knowledge of the spatiotemporal hazardsdistribution [55] and patterns threats fromof archaeological other populations. sites Havingis a powerful knowledge tool of to the understand spatiotemporal past distributionhuman- patternsenvironment of archaeological interactions sites and isto aevaluate powerful landscap tool toe understand vulnerability past to natural human-environment [56] and anthropogenic interactions andchanges to evaluate [49]. landscape vulnerability to natural [56] and anthropogenic changes [49]. AsAs can can be be seen seen in in Figure Figure6, 6, the the highest highest concentration concentration of of settlements settlements for for allall thethe periodsperiods isis locatedlocated at theat junctionthe junction of the of the Kama Kama and and Volga Volga Rivers, Rivers, this this isis representingrepresenting an an important important communication communication route. route. DuringDuring the the Palaeolithic/Mesolithic Palaeolithic/Mesolithic period (Figure (Figure 6a),6a), the hunters-fishers-gatherers hunters-fishers-gatherers population population was was wellwell adapted adapted to to the the living living aroundaround waterwater bodies an andd forests; forests; the the highest highest concentration concentration was was at atthe the junctionjunction of of Kama Kama and and Volga Volga rivers, rivers, followed followed by by the the adjacent adjacent areas areas of of upstream upstream and and downstream downstream of of the junction.the junction. A good A concentrationgood concentration can be can observed be observ oned the on Volga the River,Volga aroundRiver, around the area the where area presentlywhere thepresently city of Kazan the city is located;of Kazan the is thrivelocated; of the settlements thrive of wassettlements due to thewas optimum due to the climatic optimum conditions climatic for theconditions Preboreal for period the Preboreal [37,39], alongperiod with [37,39], the along highest with levels the ofhighest rivers levels and lakes,of rivers which and waslakes, typical which for thewas Mesolithic typical for epoch the Mesolithic [57]. The settlements epoch [57]. wereThe settl notements very homogenous were not very during homogenous this period. during However, this thisperiod. can be However, observed duringthis can the be Neolithic observed period during (Figure the 6Neolithicb), when moreperiod settlements (Figure 6b), appear when in themore area settlements appear in the area between the today Kazan city and Kama-Volga junction. The Neolithic between the today Kazan city and Kama-Volga junction. The Neolithic period is characterised by the period is characterised by the emergence of pottery, new types of stone tools and the transition to emergence of pottery, new types of stone tools and the transition to sedentism with the help of active sedentism with the help of active fishing and hunting. The majority of Neolithic sites are located on fishing and hunting. The majority of Neolithic sites are located on the remnants of the floodplain of the remnants of the floodplain of the small rivers of the Kama River tributaries or on the first terrace the small rivers of the Kama River tributaries or on the first terrace of the Kama River [40]. of the Kama River [40].

Figure 6. Location and density analysis for archaeological sites for the following periods:

(a) Palaeolithic/Mesolithic; (b) Neolithic; (c) Chalcolithic/Bronze Age; (d) Early Iron Age; (e) Migration Period; (f) Middle Ages. Water 2019, 11, 591 10 of 18

Following Chalcolithic/Bronze Age period (Figure6c), it can be observed even a higher degree of homogeneity among the settlements; this is due to the fact that the lowest levels of water were recorded in the Bronze Age. As a consequence of this, even the lowest altitudes were chosen to place the settlements, which is why the analysis shows a larger continuous surface Figure6d illustrates the density of the Early Iron Age settlements, which started to be more fragmented. The highest concentration is at the confluence of Kama-Volga Rivers and on the territory of today Bolgar, followed by scattered low-density areas the upstream Volga, at the mouth of Sviyaga River, and the downstream Volga. The settlements appear scattered because of their higher altitudinal position (higher position throughout the Holocene), due to the associated high flood levels [57]. As can be seen in Figure6e, the Migration period is characterised by spreading of population downstream Volga River, until today Ulyanovsk city. However, the highest concentration is still located at the Kama-Volga junction; the fact that during this period the area is very poorly populated is also indicated by [58]. Finally, the Middle Ages (Figure6f) show the highest fragmentation of the settlements. The highest concentration remains the same (Kama-Volga junction), while the settlements are scattered downstream and the upstream Volga until today Tolyatti and Zelenodolsk, respectively. During this period, the settlements are so scattered, due to the fact that the climatic conditions were suitable for the long-term occupation of river and lake floodplains. This is the turning point when people start to settle and make semi-permanent settlements and start off using the floodplain in order to practice agriculture on a higher level [57,59].

5.3. Cultural Heritage under Erosion Threat Since the formation of the reservoir in the middle of the 1950s, the confluence of the Kama and Volga Rivers and the left bank tributaries was flooded. As a result, many lower terraces, that were hosting archaeological sites of different periods [60], were completely flooded. The main typology of the sites is presented in Table2; therefore, out of the total of 1289 sites, 1091 are underwater or totally impacted following the building of the Kuibyshev reservoir. According to their chronology, shown in Table3, the only Palaeolithic/Mesolithic site that still exists, but is under high threat from coastal erosion, will be further analysed, based on the old Soviet Maps and modern surveys. Based on the working scenarios regarding the water level increasing and decreasing to 0.5 m and 1 m, respectively it has been observed that increasing the water level, whether, with 0.5 or 1 m, a number of two extra sites will be affected (out of 1091 already underwater or impacted). If we decrease the water level by 0.5 m or 1 m respectively, the same number of sites will remain affected—1091. Having such a large surface, water level oscillations do not affect the cultural heritage sites, unless there are variations greater than ±1 m.

5.4. Beganchik Site In order to analyse the coastal dynamics of Beganchik site, all the surveys were overlapped, and the site was divided into three sectors (Figure7), which will be further analysed separately. Beganchik site is located at the mouth of Aktai River, on the second terrace (the first terrace being flooded by Kuibyshev reservoir) of the floodplain which formed before the Holocene [61]; the altitude is between 54–60 m a.s.l. According to the general view of the site (Figure8a), the northern part of the site is represented by a very steep cliff (Figure8b) which is continually eroding. Previous preliminary studies [44] have revealed that the erosion rate is about 2–3 m/year. Water 2019, 11, 591 11 of 18

Table 2. Distribution of cultural heritage sites around Kuibyshev reservoir according to their typology.

Burial Burial Fortiﬁed Unfortiﬁed Type Building Complex Site Hoard Surface Find Tombstone Total Ground Mound (s) Settlement/HILLFORT Settlement Number 2 103 25 4 40 17 179 4 915 1289 Affected 0 82 21 3 31 14 156 4 780 1091 (under water) Not affected 2 21 4 1 9 3 23 0 135 198

Table 3. Distribution of cultural heritage sites around Kuibyshev reservoir according to their chronology.

Chalcolithic/Bronze Early Iron Migration Not Age Middle Ages Modern Time Neolithic Palaeolithic/Mesolithic Total Age Age Period Identiﬁed Number 566 45 275 148 11 164 20 60 1289 Affected 490 39 223 118 6 144 19 52 1091 (under water) Not affected 76 6 52 30 5 20 1 8 198 Water 2019, 11, x FOR PEER REVIEW 11 of 19

Water 2019, 11, 591 12 of 18 Water 2019, 11, x FOR PEER REVIEW 11 of 19

Figure 7. Shoreline limit resulted from cartographic analysis and field surveys and the division of the Figure 7. Shoreline limit resulted from cartographic analysis and ﬁeld surveys and the division of the three Figureanalysed 7. Shoreline sectors. limit resulted from cartographic analysis and field surveys and the division of the three analysedthree analysed sectors. sectors.

Figure 8. (a) General view of Beganchik site (drone ﬂight) from 2017; (b) Detail over the northern part of the site, fresh parts from the coast are visible in the water (August 2017); (c) The change of water colour, due to the clay content of the soil; (d) The northern part of the site, where the height of the coast is decreasing. Water 2019, 11, 591 13 of 18

5.4.1. Sector 1 Sector 1 was not actively eroded between 1958 and 1980 because it was protected by another island (60–90 m north-west, Figure7), as indicated by the relatively low values of the shoreline retreat (Table4); in this way, the site was protected from the mechanical action of waves (Figure8c). Later on, it can be seen that after the island disappeared, the yearly erosion has considerably increased, along with the specific land loss and volume. The direction of the Kama River flow is from north, north-east; being located at the “shelter” of Sector 2 from the speed and currents of the Kama River, this section was in some way protected. However, this sector became likely to be eroded, due to the high erosion rates of Sector 2 and having an elongated shape; this is highlighted of the specific land loss for 1958–1980.

Table 4. Detailed morphometric indicators from different observation periods for Sector 1.

Observation Shoreline Retreat Eroded Area Specific Land Loss Specific Volume Loss Years Period m m/year ha ha/year n * 10−3 ha/km * year thousands m3/km * year 1958–1980 22 32.84 1.5 2.77 0.13 253.13 12.65 1980–2008 28 33.88 1.21 1.26 0.04 133.48 6.67 2008–2014 6 11.57 1.93 0.39 0.06 191.87 9.59 2014–2017 3 17.03 5.68 0.50 0.17 469.53 23.48 2017–2018 1 3.23 3.23 0.09 0.09 276.55 13.83 Note: * defines multiplication.

Very high values of the speciﬁc land loss, in comparison with other sectors, is due to the height of the coast; which, in some parts can reach 5 m in height. Following the analysis, Sector 1 can be characterised as an extremely dangerous one.

5.4.2. Sector 2 Unlike Sector 1, Sector 2 was and still is under the direct exposure of the Kama River flow and currents. As can be seen in Table5, the specific land loss is at extremely high rates (Figure8d). This sector is the most exposed and threatened by erosion. The shoreline retreat is generally stable, varying within 2 m. According to the specific land loss indicator, it can be observed that the destruction occurred, especially within the first two periods, which is typical for the initial stage of lowland reservoir development. During this period, the extremities of this sector are cut off, after which the erosion process stabilises. Between 1958–2008, approximately 70% of the eastern part of the site was eroded. Following that, part of the river’s current’s strength was redistributed along the north-western part, which explains the sudden decrease in land loss. The height of the coast does not exceed 2 m, therefore, Sector 2 can be classified as moderately dangerous.

Table 5. Detailed morphometric indicators from different observation periods for Sector 2.

Observation Shoreline Retreat Eroded Area Specific Land Loss Specific Volume Loss Years Period m m/year ha ha/year n * 10−3 ha/km * year thousands m3/km * year 1958–1980 22 44.85 2.04 4.68 0.21 279.75 4.2 1980–2008 28 64.81 2.31 3.51 0.13 288.84 4.33 2008–2014 6 9.61 1.6 0.27 0.04 89.91 1.57 2014–2017 3 4.76 1.59 0.13 0.04 82.24 1.44 2017–2018 1 2.8 2.8 0.08 0.08 189.95 3.32 Note: * defines multiplication.

5.4.3. Sector 3 Sector 3 is located in the close proximity to Aktai River mouth, where is protected from the mechanical action of waves and Kama River strong currents. This portion of the Beganchik site shoreline is the most stable. As it can be seen from Table6, there have been no signiﬁcant changes Water 2019, 11, 591 14 of 18 regarding this part of the coast from 1958 to 2018; except the period 1980–2014, when the speciﬁc land loss is higher when compared to other periods, but considerably lower when compared with the other two sectors. The most intensive processes of coastal transformation in the study area were observed in Sectors 1 and 2, open to the destructive effect of the currents and the mechanic action of waves. The erosion intensity may vary from year to year, depending on the water level oscillations in the reservoir. In order to have a more detailed situation on the Beganchik site erosion rates, continuous annual observations are needed.

Table 6. Detailed morphometric indicators from different observation periods for Sector 3.

Observation Shoreline Retreat Eroded Area Specific Land Loss Specific Volume Loss Years Period m m/year ha ha/year n * 10−3 ha/km * year thousands m3/km * year 1958–1980 22 5.59 0.25 0.06 - 16.55 0.25 1980–2008 28 13.85 0.49 0.22 0.01 47.49 0.71 2008–2014 6 7.37 1.23 0.05 0.01 46.24 0.69 2014–2017 3 1.53 0.51 0.01 - 14.17 0.21 2017–2018 1 0.31 0.31 0.002 0.002 9.11 0.14 Note: * defines multiplication.

Particular attention should be paid to Sector 1, in which the most important part of the site is located. If the erosion rates remain stable, the site will be completely impacted in about two or three decades. This imposes urgent mitigation measures from local authorities, along with the sustainable management of cultural heritage sites.

6. Discussions Reservoir construction had a significant impact on the flow regime because the current velocity decreased. The currents are very complex, as river flows are under the direct effect of convective flows and wind effects formed in the reservoirs. These are characteristic for Kuibyshev reservoir, where wind effect and bottom relief have a high influence on hydrological conditions [51]. Volga River frames itself into the future increase of global river flow as a consequence of climate change; predictions have shown an increase of 4–8% during 2071–2100 [62]. To be more specific, future trends in the area show an increase in precipitation, temperature and in the use and levels of waters in rivers [63]. The cyclic oscillations have occurred in the Volga River basin in the last half-century; this has influenced the water level in the reservoir, and therefore the erosion rates of the shoreline. The numbers in the Tables4 and5 are related to the cyclic oscillations that brought two high-water periods (1951–1962, 1977–1995) and two low-water periods (1963–1976, 1996–present) [51]. For Sectors 1 and 2 high-water levels are associated with low erosion, while the low-water level is associated with higher erosion rates. The research presented in this paper continues our endeavour to monitor the endangered cultural heritage sites from the shoreline of the Kuibyshev reservoir [25–27,60]. Combining old maps with new data collected from field surveys shows high efficiency in establishing the erosion rates of archaeological sites located on shorelines of big reservoirs. When comparing erosion rates with the previous study [25], the average shoreline retreat is close (~3–4 m/year).

7. Conclusions In this study, the main changes along the largest reservoir in Europe—Kuibyshev (Russian Federation) were analysed, in strong connection to cultural heritage sites. Following the analysis, Sector 2 has been identiﬁed as one with the highest values of width oscillation, from 0.8–1 km to 13–36.8 km. Cultural heritage sites located in the close proximity to big rivers and/or big reservoirs are especially subjected to erosion from water, water level oscillations, and the mechanical action of waves. A diachronic analysis of the archaeological sites located along the Volga River and its main tributaries has highlighted the fact that the most inhabited area was located at the junction of Kama River into the Volga. As highlighted in our analysis, 85% of the cultural heritage around Kuibyshev Water 2019, 11, 591 15 of 18 reservoir is impacted. However, a more thorough process of monitoring and evaluating the present state of cultural heritage is needed. This has to be done with the cooperation of local authorities and stakeholders. The survey of the only left Palaeolithic site—Beganchik, has shown a fast degradation with no mitigation measures from the local authorities. Beganchik site remains promising for regular rescue archaeological excavations, despite the loss of more than a half of its surface, due to coastal erosion over the last 30 years. Working on scenarios regarding the management of archaeological sites around Kuibyshev reservoir represents one of our future goals.

Author Contributions: Conceptualisation, I.C.N. and B.U.; methodology, I.C.N., B.U. and I.G.; software, I.C.N., B.U. and I.G.; formal analysis, I.C.N. and B.U.; investigation, I.C.N., B.U. and I.G.; resources, I.C.N., B.U., I.G. and M.G.; data curation, I.C.N., B.U., I.G. and M.G.; writing—original draft preparation, I.C.N. and B.U.; writing—review and editing, I.C.N., B.U., I.G. and M.G.; visualisation, I.C.N. and B.U.; supervision, I.C.N. and B.U.; review corrections, I.C.N. and B.U. Funding: This work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University. Acknowledgments: The archaeological database was kindly provided by the Institute of Archaeology of Tatarstan Academy of Sciences (through Leonid Vyazov). James S. Williamson (Memorial University of Newfoundland, Canada) is kindly acknowledged for the English language editing of the manuscript. The authors are grateful for the constructive comments of two anonymous reviewers. Conﬂicts of Interest: The authors declare no conﬂict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

References

1. Khon, V.C.; Mokhov, I.I. The hydrological regime of large river basins in Northern Eurasia in the XX–XXI centuries. Water Resour. 2012, 39, 1–10. [CrossRef] 2. El-Younsy, A.R.; Essa, M.A.; Wasel, S.O. Sedimentological and geoenvironmental evaluation of the coastal area between Al-Khowkhah and Al-Mokha, southeastern Red Sea, Republic of Yemen. Environ. Earth. Sci. 2017, 76, 50. [CrossRef] 3. Romanescu, G.; Mihu-Pintilie, A.; Ciurte, D.L.; Stoleriu, C.C.; Cojoc, G.M.; Tirnovan, A. Allocation of flood control capacity for a multireservoir system. Case study of the Bistrita River (Romania). Carpath. J. Earth. Environ. 2019, 14, 223–234. [CrossRef] 4. Avakyan, A.B.; Podol’skii, S.A. Impact of reservoirs on the fauna. Water Resour. 2002, 29, 123. [CrossRef] 5. Berka, R. Inland Capture Fisheries of the USSR; FAO Fisheries Technical Paper 311; FAO (Food and Agriculture Organization): Rome, Italy, 1989; p. 143. 6. Vilmundardóttir, O.K.; Magnússon, B.; Gísladóttir, G.; Thorsteinsson, T. Shoreline erosion and aeolian deposition along a recently formed hydro-electric reservoir, Blöndulón, Iceland. Geomorphology 2010, 114, 542–555. [CrossRef] 7. Su, X.; Nilsson, C.; Pilotto, F.; Liu, S.; Shi, S.; Zeng, B. Soil erosion and deposition in the new shorelines of the Three Gorges Reservoir. Sci. Total Environ. 2017, 599–600, 1485–1492. [CrossRef] 8. Jayakumar, K. Analysis of shoreline changes along the coast of Tiruvallur District, Tamil Nadu, India. J. Geogr. Cartogr. 2018, 1, 1–9. [CrossRef] 9. Svyatko, S.V.; Reimer, P.J.; Schulting, R. Modern freshwater reservoir offsets in the Eurasian steppe: Implications for archaeology. Radiocarbon 2017, 59, 1597–1607. [CrossRef] 10. Górski, K.; van den Bosch, L.V.; van den Wolfshaar, K.E.; Middelkoop, H.; Nagelkerke, L.A.J.; Filippov, O.V.; Zolotarev, D.V.; Yakovlev, S.V.; Minin, A.E.; Winter, H.V.; et al. Post-damming flow regime development in a large lowland river (Volga, Russian Federation): Implications for floodplain inundation and fisheries. River Res. Appl. 2012, 28, 1121–1134. [CrossRef] 11. Majerová, L.; Bábek, O.; Navrátil, T.; Nováková, T.; Štojdl, J.; Elznicová, J.; Hron, K.; Matys Grygar, T. Dam reservoirs as an efficient trap for historical pollution: The passage of Hg and Pb through the OhˇreRiver, Czech Republic. Environ. Earth. Sci. 2018, 77, 574. [CrossRef] 12. Pranzini, E. Coastal erosion and shore protection: A brief historical analysis. J. Coast. Conserv. 2017, 22, 827–830. [CrossRef] Water 2019, 11, 591 16 of 18

13. Pourkerman, M.; Marriner, N.; Morhange, C.; Djamali, M.; Amjadi, S.; Lahijani, H.; Beni, A.N.; Vacchi, M.; Tofighian, H.; Shah-Hoessein, M. Tracking shoreline erosion of “at risk” coastal archaeology: The example of ancient Siraf (Iran, Persian Gulf). Appl. Geogr. 2018, 101, 45–55. [CrossRef] 14. Chapman, H.P.; Fletcher, W.G.; Thomas, G. Quantifying the effects of erosion on the archaeology of intertidal environments. A new approach and its implications for their management. Conserv. Manag. Arch. 2001, 4, 233–240. [CrossRef] 15. Jazwa, C.S.; Johnson, K.N. Erosion of coastal archaeological sites on Santa Rosa Island, California. West. N. Am. Nat. 2018, 78, 302–327. [CrossRef] 16. Pantusa, D.; D’Alessandro, F.; Riefolo, L.; Principato, F.; Tomasicchio, G.R. Application of a Coastal Vulnerability Index. A Case Study along the Apulian Coastline, Italy. Water 2018, 10, 1218. [CrossRef] 17. Westley, K. Refining Broad-Scale Vulnerability Assessment of Coastal Archaeological Resources, Lough Foyle, Northern Ireland. J. Isl. Coast. Archaeol. 2018.[CrossRef] 18. O’Rourke, M.J.E. Archaeological site vulnerability modelling: The influence of high impact storm events on models of shoreline erosion in the western Canadian Arctic. Open Archaeol. 2017, 3, 1–17. [CrossRef] 19. Flatman, J. Conserving marine cultural heritage: Threats, risks and future priorities. Conserv. Manag. Arch. 2009, 11, 5–8. [CrossRef] 20. Dillenia, I.; Troa, R.; Triarso, E. In situ preservation of marine archaeological remains based on geodynamic conditions, Raja Ampat, Indonesia. Conserv. Manag. Arch. 2016, 18, 364–371. [CrossRef] 21. Howard, P.; Pinder, D. Cultural heritage and sustainability in the coastal zone: Experiences in south-west England. J. Cult. Herit. 2003, 4, 57–68. [CrossRef] 22. Usmanov, B.; Nicu, I.C.; Gainullin, I.; Khomyakov, P. Monitoring and assessing the destruction of archaeological sites from Kuibyshev reservoir coastline, Tatarstan Republic, Russian Federation. A case study. J. Coast. Conserv. 2018, 22, 417–429. [CrossRef] 23. Demin, A.P. The efficiency of water resources management in Volga basin. Water Resour. 2005, 32, 594–604. [CrossRef] 24. Micklin, P.P. Environmental costs of the Volga-Kama cascade of power stations. Water Resour. Bull. 1974, 10, 565–572. [CrossRef] 25. Avakyan, A.B. Volga-Kama cascade reservoirs and their optimal use. Lakes Reserv. Res. Manag. 1998, 3, 113–121. [CrossRef] 26. Gainullin, I.I.; Sitdikov, A.G.; Usmanov, B.M. Destructive abrasion processes study in archaeological sites placement (Kuibyshev and Nizhnekamsk reservoirs, Russia). In Proceedings of the SGEM 2014 Scientific SubConference on Anthropology, Archaeology, History and Philosophy, Albena, Bulgaria, 3–9 September 2014; Volume 3, pp. 339–346. [CrossRef] 27. Gainullin, I.I.; Khomyakov, P.V.; Sitdikov, A.G.; Usmanov, B.M. Study of anthropogenic and natural impacts on archaeological sites of the Volga Bulgaria period (Republic of Tatarstan) using remote sensing data. Proc. SPIE 9688 2016.[CrossRef] 28. Nicu, I.C. Natural risk assessment and mitigation of cultural heritage sites in North-eastern Romania (Valea Oii river basin). Area 2019, 51, 142–154. [CrossRef] 29. Döring, M.; Ratter, B.M.W. Coastal landscapes: The relevance of researching coastscapes for managing coastal change in North Frisia. Area 2018, 50, 169–176. [CrossRef] 30. Ratushnyak, A.A. The role of aquatic macrophytes in hydroecosystems of Kuibyshev Reservoir (Republic of Tatarstan, Russia). Am.-Eurasian J. Agric. Environ. Sci. 2008, 4, 1–8. 31. Zakonnov, V.V.; Ivanov, D.V.; Zakonnova, A.V.; Kochetkova, M.Y.; Malanin, V.P.; Khaidarov, A.A. Spatial and temporal transformations of bottom sediments in the Middle Volga reservoirs. Water Resour. 2007, 34, 540–548. [CrossRef] 32. Panin, A.; Matlakhova, E. Fluvial chronology in the East European Plain over the last 20 ka and its palaeohydrological implications. Catena 2015, 130, 46–61. [CrossRef] 33. Koposov, E.V.; Sobol, I.S.; Ezhkov, A.N. Prognozirovanie abrazionnoy i opolznevoy opasnosti poberezhiy Volzhskikh vodokhranilishch (Peculiar Predicting of Formation of Abrasion and Landslide Hazard Shores of the Volga Water Reservoirs). Vestnik MGSU 2013, 6, 170–176. (In Russian) [CrossRef] 34. Golosov, V.; Yermolaev, O.; Rysin, I.; Vanmaercke, M.; Medvedeva, R.; Zaytseva, M. Mapping and spatial-temporal assessment of gully density in the Middle Volga region, Russia. Earth Surf. Process. Landf. 2018, 43, 2818–2834. [CrossRef] Water 2019, 11, 591 17 of 18

35. Biswas, A.K. Impacts of large dams: Issues, opportunities and constraints. In Impacts of Large Dams: A Global Assessment; Tortajada, C., Altinbilek, D., Biswas, A.K., Eds.; Springer-Verlag: Berlin Heidelberg, Germany, 2012; pp. 1–18. 36. Petrov, N. Cultural heritage management in Russia. In Cultural Heritage Management. A Global Perspective; Mauch, M.P., Smith, G.S., Eds.; University Press of Florida: Gainesville, FL, USA, 2010; pp. 153–161. 37. Leonova, N.B. The Upper Palaeolithic of the Russian steppe zone. J. World Prehist. 1994, 8, 169–210. [CrossRef] 38. Galimova, M.S. Final Palaeolithic—Early Mesolithic cultures with trapezia in the Volga and Dnieper basins: The question of origin. Archaeol. Baltica 2005, 7, 136–148. 39. Zhilin, M.G. Early Mesolithic hunting and ﬁshing activities in Central Russia: A review of the faunal and artefactual evidence from wetland sites. J. Wetl. Archaeol. 2014, 14, 91–105. [CrossRef] 40. Lychagina, E.L.; Vybornov, A.A. Chronology of Kama Neolithic culture. Doc. Praehist. 2017, 152–161. [CrossRef] 41. Demkina, T.S.; Borisov, A.V.; Demkin, V.A.; Khomutova, T.E.; Kuznetsova, T.V.; El’tsov, M.V.; Udal’tsov, S.N. Paleoecological Crisis in the Steppe of the Lower Volga Region in the Middle of the Bronze Age (III-II centuries BC). Eurasian Soil Sci. 2017, 50, 791–804. [CrossRef] 42. Patrushev, V.S. Textile ceramics of the Early Iron Age in the Ardino settlement. Perm Univ. Herald-Hist. 2017, 36, 63–73. [CrossRef] 43. Kazakov, E.P. Pamyatniki epohi kamnya v Zakame (Arheologicheskiy ocherk). Ch. 1. Stone Age Sites in the Trans-Kama Region (Archaeological Essay). Part 1; Institute of History named after Sh. Marjani: Kazan, Russia, 2011. (In Russian) 44. Galimova, M.S. Pamyatniki pozdnego paleolita i mezolita v uste reki Kamyi (Upper Palaeolithic and Mesolithic Sites at the Mouth of the Kama River); «Yanus-K» Publ.: Moskow-Kazan, Russia, 2001. (In Russian) 45. Galimova, M.S. Otchet ob arheologicheskih issledovaniyah stoyanki Beganchik, raspolozhennoy v zone abrazionnoy deyatelnosti Kuybyishevskogo vodohranilischa v Spasskom rayone Respubliki Tatarstan v 2013 godu (Report on Archaeological Investigation the Site of Beganchik Located in the Area of the Abrasion Activity of the Kuybyshev Reservoir in the Spassky District of the Republic of Tatarstan in 2013); The Archive of the Institute of Archaeology of Russian Academy of Sciences: Kazan, Russia, 2017. (In Russian) 46. Callow, J.N.; May, S.M.; Leopold, M. Drone photogrammetry and KMeans point cloud ﬁltering to create high resolution topographic and inundation models of coastal sediment archives. Earth Surf. Process. Landf. 2018, 43, 2603–2615. [CrossRef] 47. Kinda, A. Nature of old maps: As primary source materials for historical geography. Earth Sci. 2018, 7, 260–267. [CrossRef] 48. Gainullin, I.I.; Kasimov, A.; Khomyakov, P.V.; Usmanov, B.M. An integrated approach for Medieval hillforts study (Republic of Tatarstan, Russia). In Proceedings of the 3rd International Association of SGEM Conference, Albena, Bulgaria, 30 September 2016; Volume 3, pp. 247–254. [CrossRef] 49. Nicu, I.C. Cultural heritage assessment and vulnerability using Analytic Hierarchy Process and Geographic Information Systems (Valea Oii catchment, North-eastern Romania). An approach to historical maps. Int. J. Disaster Risk Reduct. 2016, 20, 103–111. [CrossRef] 50. Nicu, I.C. Tracking natural and anthropic risks from historical maps as a tool for cultural heritage assessment: A case study. Environ. Earth. Sci. 2017, 76, 330. [CrossRef] 51. Litvinov, A.S.; Mineeva, N.M.; Papchenkov, V.G.; Korneva, L.G.; Lazareva, V.I.; Shcherbina, G.K.; Gerasimov, Y.V.; Dvinskikh, S.A.; Noskov, V.M.; Kitaev, A.B.; et al. Volga River Basin. In Rivers of Europe; Tockner, K., Uehlinger, U., Robinson, C.T., Eds.; Academic Press: Cambridge, MA, USA, 2009; pp. 23–57. 52. Melnikova, G.L. Peculiarities of Shallows in Regulated Reservoirs. In IIASA Professional Paper; IIASA (International Institute for Applied System Analysis): Laxenburg, Austria, 1977; p. 77. 53. Nicu, I.C. Hydrogeomorphic Risk Analysis Affecting Chalcolithic Archaeological Sites from Valea Oii (Bahlui) Watershed, Northeastern Romania; An Interdisciplinary Approach, 1st ed.; Springer: Cham, Switzerland, 2016. 54. Capuzzo, G.; Zanon, M.; Dal Corso, M.; Kirleis, W.; Barceló, J.A. Highly diverse Bronze Age population dynamics in Central-Southern Europe and their response to regional climatic patterns. PLoS ONE 2018, 13. [CrossRef][PubMed] 55. Nicu, I.C. Application of analytic hierarchy process, frequency ratio, and statistical index to landslide susceptibility: An approach to endangered cultural heritage. Environ. Earth Sci. 2018, 77, 79. [CrossRef] Water 2019, 11, 591 18 of 18

56. Hosner, D.; Wagner, M.; Tarasov, P.E.; Chen, X.; Leipe, C. Spatiotemporal distribution patterns of archaeological sites in China during the Neolithic and Bronze Age: An overview. Holocene 2016, 26, 1576–1593. [CrossRef] 57. Panin, A.V.; Nefedov, V.S. Analysis of variations in the regime of rivers and lakes in the Upper Volga and Upper Zapadnaya Dvina based on archaeological-geomorphological data. Water Resour. 2010, 37, 16. [CrossRef] 58. Ivanov, V.A. Southern CIS-Urals in the Great Migration Period—Archaeological and geographical context. Povolzhskaya Arkheol. 2017, 4, 8–23. [CrossRef] 59. Demkin, V.A.; Yakimov, A.S.; Alekseev, A.O.; Kashirskaya, N.N.; El’tsov, M.V. Paleosol and paleoenvironmental conditions in the Lower Volga steppes during the Golden Horde period (13th–14th centuries AD). Eurasian Soil Sci. 2006, 39, 115–126. [CrossRef] 60. Gainullin, I.I.; Khomyakov, P.V.; Sitdikov, A.G.; Usmanov, B.M. Qualitative assessment of the medieval fortifications condition with the use of remote sensing data (Republic of Tatarstan). Proc. SPIE 10444 2017. [CrossRef] 61. Yermolaev, O.P.; Igonin, M.E.; Bubnov, A.Y.; Pavlova, S.V. Landshaftyi Respubliki Tatarstan. Regionalnyiy Landshaftno-Ekologicheskiy Analiz (Landscapes of the Republic of Tatarstan. Regional Landscape-Ecological Analysis); «Slovo» Publ.: Kazan, Russia, 2007. (In Russian) 62. Falloon, P.D.; Betts, R.A. The impact of climate change on global river flow in HadGEM I simulations. Atmos. Sci. Lett. 2006, 7, 62–68. [CrossRef] 63. Kouzmina, J.V.; Treshkin, S.E. Climate changes in the basin of the Lower Volga and their influence on the ecosystem. Arid Ecosyst. 2014, 4, 142–157. [CrossRef]

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).